Gradiometer integrating pickup coils and magnetic field measurement system

a pickup coil and magnetic field technology, applied in the direction of magnetic field measurement using superconductive devices, instruments, applications, etc., can solve the problems of not knowing the configuration that meets the three conditions, the and the inevitable error of a measured magnetic field

Inactive Publication Date: 2002-08-22
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

2, 3, 4 also have a problem left unsolved that environmental magnetic field noise is introduced from wires for installation, since the magnetic coils are not integrated with the SQUID, to inevitably cause errors in a measured magnetic field.
Also, Prior Art 6 has a problem that when a substrate on which the pickup

Method used

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  • Gradiometer integrating pickup coils and magnetic field measurement system
  • Gradiometer integrating pickup coils and magnetic field measurement system
  • Gradiometer integrating pickup coils and magnetic field measurement system

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Experimental program
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first embodiment

[0101] (First Embodiment)

[0102] A first embodiment of the present invention provides a gradiometer integrating pickup coils in flux transformer configuration. The gradiometer according to the first embodiment is configured to simultaneously detect (.DELTA.Bz / .DELTA.x) and (.DELTA.Bz / .DELTA.y). In the following, the first embodiment will be described with reference to FIGS. 3 to 6. It should be noted that in these figures, partial alterations and omissions are made for purposes of explanation, and the dimensions are not necessarily on scale.

[0103] A superconductor in the present invention may be either a low-critical-temperature superconductor which operates at the temperature of liquid helium, or a high-critical-temperature superconductor which operates at a higher temperature. Strictly speaking, the structure of Josephson junction differs from one type to another of superconductor. However, since this aspect is not related to the present invention, a convenient structure will be re...

second embodiment

[0115] (Second Embodiment)

[0116] A second embodiment of the present invention provides a gradiometer integrating pickup coils in flux transformer configuration. The gradiometer according to the second embodiment is configured to simultaneously detect (.DELTA.Bz / .DELTA.x) and (.DELTA.Bz / .DELTA.y).

[0117] FIG. 7 is a diagram for explaining an equivalent circuit of the gradiometer integrating pickup coils in flux transformer configuration according to the second embodiment. Pickup coils 11Xp, 11Xn are magnetically connected to a differential SQUID (1X) through input coils 2, while pickup coils 11Yp, 11Yn are magnetically connected to a differential SQUID (1Y) through input coils 2. The differential SQUIDs (1X, 1Y) are in a parallel configuration in which two superconducting loops are connected in parallel when viewed from Josephson junctions 5.

[0118] FIG. 8 is a diagram for explaining the structure of a central portion of the gradiometer according to the second embodiment shown in FIG. ...

third embodiment

[0119] (Third Embodiment)

[0120] A third embodiment of the present invention provides a gradiometer integrating pickup coils in flux transformer configuration. The gradiometer integrating pickup coils according to the third embodiment is configured to simultaneously detect (.DELTA.Bz / .DELTA.x) and (.DELTA.Bz / .DELTA.y).

[0121] FIG. 9 is a diagram for explaining an equivalent circuit of the gradiometer integrating pickup coils in flux transformer configuration according to the third embodiment. Pickup coils 11Xp, 11Xn are magnetically coupled to a differential SQUID (1X) through input coils 2, while pickup coils 11Yp, 11Yn are magnetically coupled to a differential SQUID (1Y) through input coils 2. Loops formed of the pickup coils 11Xp, 11Xn are connected in series to form an 8-figured shape as a whole such that currents flow through the loops in opposite directions to each other with respect to the application of a uniform field. Likewise, loops formed of the pickup coils 11Yp, 11Yn ar...

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PUM

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Abstract

A gradiometer integrating pickup coils comprises pickup coils 11Xp, 11Xn magnetically connected to a SQUID through associated input coils 2, and pickup coils 11Yp, 11Yn magnetically connected to a SQUID through associated input coils 2, respectively. Two superconducting loops are connected in series to each of the SQUIDs, when viewed from Josephson junctions 5. The input coils 2 form superconducting closed loops together with the pickup coils 11Xp, 11Xn, 11Yp, 11Yn associated therewith. The SQUIDs are respectively connected to form an 8-figured shape as a whole such that currents flow in two superconducting loops of each SQUID in opposite directions to each other, with respect to the application of a uniform field, in order to reduce environmental magnetic field noise.

Description

[0001] The present application is relevant to U.S. patent application Ser. No. being filed by Daisuke Suzuki, Tsuyoshi Miyashita, Akihiko Kandori, Keiji Tsukada and Kouich Yokosawa, and assigned to the present assignee, based on Japanese Patent Application No. 2001-044424 filed on Feb. 21, 2001, and U.S. patent application Ser. No. being filed by Daisuke Suzuki, Atsushi Ninomiya, Tsuyoshi Miyashita, Akihiko Kandori, Keiji Tsukada and Kouich Yokosawa, and assigned to the present assignee, based on Japanese Patent Application No. 2000-334921 filed on Oct. 30, 2000. The contents of these applications are incorporated herein by reference.[0002] The present invention relates to a SQUID (Superconducting QUantum Interference Device) integrating pickup coils which can highly sensitively detect a magnetic field generated from a subject under testing, and more particularly, to a magnetic field measurement system using the SQUID integrating pickup coils. More specifically, the present inventio...

Claims

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Application Information

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IPC IPC(8): A61B5/05G01R33/022G01R33/035
CPCG01R33/022G01R33/0358
Inventor YOKOSAWA, KOICHISUZUKI, DAISUKETSUKADA, KEIJIMIYASHITA, TSUYOSHIKANDORI, AKIHIKO
Owner HITACHI LTD
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